Stats in R: Class Test 2

Question 1

What does a Chi-Squared do?

Answer 1

Provides an analysis of frequency data between observed and expected data

Question 2

What does a t-test analyse?

Answer 2

Variance

Question 3

What does a t-test compare specifically?

Answer 3

Means and variances of two or more datasets

Question 4

When is a t-test suitable?

Answer 4

When data is normally distributed or sample size is large

Question 5

What do one-sample and two=-ample t-tests against?

Answer 5

A one-sample t-test, tests against a regulatory limit or identified value and a two-sample for one mean against the other

Question 6

ANOVA analysis should be used on what kind of data?

Answer 6

Categorical

Question 6

How should the Residual and QQ Plot look for ANOVA model checking?

Answer 6

Residuals should have no obvious structure between stack and QQ plot should have all points on the 45 degree line or close

Question 6

When is ANOVA appropriate?

Answer 6

When comparing means and variances of two or more datasets and if the dataset includes replication (variation)

Question 7

When should a transform be used?

Answer 7

When data is non-normal and positively skewed and model checking is not successful

Question 8

How is a maximal model created?

Answer 8

Include all EVs as well as any interaction between them with *

Question 9

How is the Minimum Sufficient Model reached?

Answer 9

Remove the least significant variable, one by one until all variables are significant

Question 10

What does the Tukey “Honest Significant Difference” function identify?

Answer 10

Determines between which groups that there is a significant difference